Derotational osteotomy at the distal femur is effective to treat patients with patellar instability

Abstract

Purpose

Increased femoral antetorsion influences patellofemoral joint kinematics. The aim of this study was to retrospectively evaluate the clinical outcome after derotational osteotomies and combined procedures in patients with patellofemoral instability.

Methods

All patients with derotational osteotomies and combined procedures in patients with patellofemoral instability and increased femoral antetorsion performed between 2007 and 2016 were retrospectively analyzed. Exclusion criteria were open growth plates, posttraumatic deformities, and a follow-up period less than 12 months. Simple radiography and magnetic resonance imaging to evaluate cartilage lesions, trochlear dysplasia, tubercle distance, and osseous malalignment as frontal axis and torsion were performed on every patient. Patients were evaluated pre- and postoperatively using the visual analog scale (VAS) for pain, the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, the subjective IKDC evaluation form, the Lysholm score, and the Tegner activity score.

Conclusion

Combined derotational osteotomy is a suitable treatment for patellar instability due to torsional malformity, as it leads to a significant reduction of pain, and a significant increase of knee function with good-to- excellent results in the short-term follow-up.

Level of evidence

IV.

Keywords

Notes

Author contributions

FI had done several surgeries within the study group, carried out the study design and drafted the manuscript. MC helped with study design, patient acquisition, data processing and statistical analysis. FL helped with data collection and interpretation of the data, and performed surgeries. FD carried out coordination of the patient’s follow-up, participated in surgeries and helped to draft the manuscript. KB performed the surgeries, assessed the radiological analysis and served as internal reviewer of the manuscript. AI performed the surgeries, assessed the radiological analysis and served as internal reviewer of the manuscript. EH made substantial contribution to the study design, defined study variables and drafted the manuscript. All authors read and approved the final manuscript.

Funding

There was no financial conflict of interest with regards to this study.

Compliance with ethical standards

Conflict of interest

FI, MC, FL, FD report none. KB is a consultant of Arthrex GmbH. AI is a consultant for Arthrex and receives grants and royalties from Arthrex.

Ethical approval

Ethical approval was obtained from the Ethics Committee of the Technical University Munich. All procedures performed were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Declaration of Helsinki and its later amendments or comparable ethical standards.

Informed consent

Informed consent was obtained from all individual participants included in the study.